Add exit() function just to prevent loads of the standard library from being included in the build.
diff --git a/Demo/CORTUS_APS3_GCC/Demo/main.c b/Demo/CORTUS_APS3_GCC/Demo/main.c
index 562ec4f..093bac9 100644
--- a/Demo/CORTUS_APS3_GCC/Demo/main.c
+++ b/Demo/CORTUS_APS3_GCC/Demo/main.c
@@ -284,5 +284,11 @@
 }
 /*-----------------------------------------------------------*/
 
+/* Provide an exit function to prevent a whole load of standard library functions
+being brought into the build. */
+void exit( int status )
+{
+	for( ;; );
+}